Investigation of Crack Propagation Behaviors in a Fillet Welded Joint Employing X-FEM

Abstract

A fillet welded joint has been used for ship and offshore structures. During the welding process, unwelded parts remain in the structure. When a crack propagates from the web plate to the joint across the unwelded part, interesting crack propagation (CP) phenomena, i.e., crack front separation and crack coalescing, were observed. In the present study, threedimensional CP simulation is carried out to carefully investigate the fracture behaviors. X-FEM, a powerful computational fracture mechanics analysis method, is adopted. A crack option in an open source CAE software Code Aster is chosen. It is found that a modification is needed to analyze the complicated fracture behaviors appropriately. The analysis control file and source code have been modified to improve accuracy for the evaluation of fracture mechanics parameter and crack path. With the present approach, the complicated fracture phenomena can be solved effectively. The fracture behavior is discussed well with the crack trajectories and history of the fracture mechanics parameters for the propagating crack.